There has been presented, as a one kind of industrial vehicles including forklifts, an industrial vehicle mounted thereon with a tilt type cabin. Such an industrial vehicle has the structure that a cabin is pivotally supported at its one side to a vehicle frame so as to be downward tiltable on one side of a vehicle body. In the industrial vehicle having the above-mentioned configuration, the cabin is tilted down so as to open an engine compartment underneath the cabin in order to readily carry out inspection and maintenance or the like (refer to, for example, Patent Document 1 (Japanese Patent Laid-Open No. 2000-118448)).
Referring to FIG. 5 which shows a forklift as an example in a tilt-up condition, a forklift 50 as shown incorporates a vehicle body 51 and a cabin 52 arranged above the vehicle body. The cabin 52 is box-like and is provided therein with a seat for a worker, and a control portion. The lower part of the cabin 52 is pivotally supported at its one side to the vehicle body through pivotable hinges or the like, and is downward tiltable toward one side of the vehicle body by means of a hydraulic mechanism which is not shown. Further, the cabin 52 has a support part for fixing the opening side thereof in a normal condition in which the cabin 50 is returned to an operating position.
Among tilt type cabins as stated above, there has been presented the one which incorporates a lock mechanism for holding the cabin having been tilted down.
Patent Document 2 (Japanese Patent Laid-Open No. 2006-76389) discloses a cabin lock mechanism comprising a lock plate provided to a cabin which is pivotally mounted on a vehicle body, and a mount portion which is engageable with a fitting hole formed in the lock plate and which is secured to the vehicle body, the loc plate and the mount portion constituting a lock mechanism, the mount portion having a locking groove engageable with a part of the peripheral part of the fitting hole in the lock plate, and the lock plate being held so as to be slidably supported by a guide mechanism which is attached to a bracket extending from the cabin. Thus, the cabin can be locked and mounted by sliding the lock plate.
Thus, with the lock mechanism disclosed in Patent Document 2, the cabin can be tilted down under the operation of an urging member such as a torsion bar, a spring or the like during inspection and maintenance by releasing the lock mechanism, and after the completion of the inspection and maintenance, the cabin is lowered and is then locked to the vehicle body. However, should the cabin be unexpectedly unlocked in the tilt-up condition, the cabin would be lowered during the inspection and maintenance or the like, resulting in an extremely dangerous condition. However, in the conventional industrial vehicle, a safety mechanism for preventing the cabin from being lowered during working has not yet been, indeed, considered.